This grant request is for the purchase of a double-focusing high resolution mass spectrometer and data system and accessories which will be used to support the research efforts of investigators in the Department of Chemistry at the University of Minnesota. We propose to replace aging instrumentation acquired in 1972 and 1977 that is becoming increasingly difficult to maintain at a level of performance that research interests require, and to add LC-MS capability, which is currently not available to these users. Integrated into the Departmental Mass Spectrometry facility, the new instrumentation will provide nominal and accurate mass capabilities in EI, CI, and thermospray ionization modes, with positive- and negative- ion capabilities, using various sample inlet systems (solids probe, capillary GC, thermospray HPLC).